1. Field of Invention
This invention relates to the obstruction or barricading of confined open areas, such as underground mine entries, tunnels, subways and the like, to isolate fire or smoke generated in one location from spreading to other areas. More particularly, this invention relates to expandable barricades for obstructing an entry opening.
2. State of the Art
Every year hundreds of lives are lost or endangered in mine disasters because of fires or explosions which cannot be contained to a specific area. Additionally, fires in mines, if not contained to one area, can damage interconnected mine entries and make access to the mine difficult or impossible. Also, the spread of uncontrolled fires in coal mines, for example, consumes large quantities of valuable coal, and destroys large amounts of valuable equipment and infrastructure.
A number of barriers have been designed to block off mine entries or other types of passageways after an explosion or fire has occurred. For example, U.S. Pat. No. 4,077,474 to Hattori discloses a curtain of fire-resistant fabric releasable from a frame above an entry. U.S. Pat. No. 3,831,318 to Richmond discloses a series of inflatable bags which, when inflated with air, converge together to block the opening or passageway. Similarly, U.S. Pat. Nos. 4,102,138 and 4,036,024 to Dreker disclose an inflatable bag, initially filled with air, which is later filled with a material of a type which permanently blocks the mine passageway. U.S. Pat. No. 3,645,337 to Livingston discloses an overhead chamber through which a gel is excreted to form a curtain of synthetic material which dries into a solid blockade. And U.S. Pat. No. 4,023,372 to Preslar discloses a partially inflatable wall of fabric which allows passage therethrough.